Various techniques are known in the art for withdrawing samples of biological fluids during collection. Sampling systems designed for blood sampling during blood donation include, for example, a blood sample bag preconnected to the blood donor line (U.S. Pat. No. 2,950,716) and a preconnected vacuum tube collector (ADAM Medical Products Ltd.; Ashdod, Israel). Both fluid sampling systems involve "opening" the collection tubing network to a removable sample container, however, and thus compromise the sterile fluid pathway. The potential for bacterial contamination of the collected product thus limits use of these direct sampling devices to the sampling of nonperishable fluids, i.e., fluids destined for immediate refrigeration or use.
Sampling techniques and devices designed for use with "closed" collection systems have also been proposed. As used herein, a "closed" collection system refers to a functionally closed fluid collection system sealed to ensure fluid sterility either by hermetically sealing the entire system or by providing sterile barrier filters at all connections to the collection system, U.S. Pat. No. 4,978,446 illustrates a functionally closed system employing a sterile barrier filter. Closed collection systems are typically used to collect biological fluids not destined for immediate transfusion or processing, or substances whose chemical or physical integrity is compromised by cooling. Sampling devices adapted for closed collection systems generally comprise a sample inlet tube positioned between the sample container and the fluid pathway, said inlet tube comprising a clamping means to seal off the sample reservoir from the sterile fluid pathway prior to withdrawing the sample.
Although these sampling devices have been successfully used to sample donor whole blood during blood and platelet collection, such devices are deficient in several respects. First, none of these systems assure a hermetic fluid-tight seal between the sample reservoir and the fluid pathway. The clamp mechanism can fail during operation causing leakage of contaminated fluid into the sterile fluid pathway, or the operator can inadvertently fail to seal off the fluid pathway from the sample reservoir prior to removing a sample. In either event, the collected product must be immediately processed or discarded. Second, removal of the sample reservoir requires cutting the sample inlet tube using a knife or scissors, a procedure which exposes the operator to contact with the fluid which may be infectious or otherwise hazardous. The use of the knife or scissors also increases the time required. The contaminated knife or scissors must be handled with care to avoid contact with the fluid, and must be cleaned or sterilized after each use. Third, after the sample reservoir is removed from the collection system, the fluid is transferred from the sample container into test tubes for analysis, a procedure which creates air-borne particles and splashing, again exposing the operator to potentially hazardous fluid. Alternatively, transfer to test tubes is accomplished using conventional hypodermic needles and syringes. Although this latter method minimizes fluid spillage, it generates used needles and the problems associated therewith, including disposal concerns and the risk of accidental punctures.
A need therefore exists for a device for removing biological fluid samples during collection without opening the collection tubing system and thereby compromising the sterile fluid pathway, and which also minimizes exposure to the potentially infectious or hazardous fluid during sample handling and processing.